Cambridge policemen, known as “Bulldogs”, lined up for the University Bulldogs Chase, dressed in morning coats and top hats, 7th March 1936. (Photo by H. Allen/Topical Press Agency/Getty Images)

A woman walks past a caricature of Britain's Foreign Secretary Boris Johnson in east London, Britain November 18, 2016. (Photo by Andrew Winning/Reuters)

Riot police fire tear gas during a protest by supporters of Dilma Rousseff in Sao Paulo, Brazil August 31, 2016. (Photo by Paulo Whitaker/Reuters)

Black-headed gulls sit on pickets at a riverside in Tokyo, Japan, December 27, 2015. (Photo by Toru Hanai/Reuters)

A woman waters the plants outside her house in an alley at a slum in Mumbai October 28, 2014. (Photo by Danish Siddiqui/Reuters)

Pope Francis attends a circus performance during his weekly general audience at Paul VI hall on December 22, 2016 at the Vatican. (Photo by Alberto Pizzoli/AFP Photo)

Staff of a boat restaurant on the Taedong River line up at the entrance as they wait to greet customers Sunday, June 18, 2017, in Pyongyang, North Korea. The boat is berthed along the river, which is the fifth longest river on the Korean Peninsula and runs through the country's capital, Pyongyang. (Photo by Wong Maye-E/AP Photo)

A young boy plugs his ears as his sister (C) and nanny (L) watch from Gravelly Point Park as planes land at Reagan National Airport in Arlington, Virginia on June 29, 2017. President Donald Trump' s travel ban on people from six mostly Muslim countries will come into force late Thursday, as controversy swirls over who qualifies for an exemption based on family ties. (Photo by Jim Watson/AFP Photo)